A longstanding problem in the operation of heating, ventilating and air conditioning (HVAC) equipment is compensation by the equipment controls, including the temperature sensor or thermostat, for example, in conditions of relatively rapidly changing outdoor temperatures. It is desirable to be able to anticipate the rate of temperature change and to compensate for such change to maintain heating or cooling of the enclosed space being serviced by the HVAC equipment. The ability to compensate for differential temperatures between the outdoor temperature and the temperature of the enclosed space can be aggravated when the structure defining the enclosed space includes a relatively large amount of glass or window area. Efforts to compensate or correct the thermostat setpoint temperature in prior art control systems have relied on radiant temperature sensors, for example. Efforts have also been made to develop methods for predicting the effect of windows on thermal comfort, that is, by providing means to analyze long wave radiation, induced drafts and solar load effects. Although windows or glass walls are not necessarily the primary element effecting the comfort of occupants of an enclosed space, when an occupant is very close to a window or glass wall such structures can become influential and efforts have been made to develop so-called window comfort indexes.
Notwithstanding the state of the art and prior efforts to compensate for temperature differentials between indoor and outdoor temperatures and the amount of window or glass area delimiting an enclosed space being serviced by HVAC equipment, the present invention provides a system and method for improving the thermal comfort level of an enclosed space dependent on the difference between the outdoor and indoor temperatures and the glass or window area exposed to the outdoor temperature as a percentage of the total wall area defining the enclosed space, for example.